This invention relates to a four-cycle engine for a marine propulsion device and more particularly to an improved method for lubricating the camshaft of an internal combustion engine.
As is well known, most internal combustion engines operating on four-stroke cycle principles are provided with a pressure lubricating system for lubricating the components of the engine. Quite frequently, as with the case of an overhead camshaft engine, the camshaft is located remotely from the oil pump. As a result, the critical bearing surfaces of the camshaft such as the cam lobes and the valves or rocker arms which they engage do not receive lubricant immediately upon starting of the engine. Frequently, the engine may run for some brief period of time before lubricant reaches these critical components.
When the engine is operated in conjunction with an outboard motor, it is the normal practice to dispose the engine so that its output shaft rotates about a vertically extending axis. When this is done, the camshaft is also supported for rotation about a vertically extending axis and this further complicates the problem in lubricating the camshaft and specifically the cam lobes and the elements which they operate.
It is, therefore, a principal object of this invention to provide an improved lubricating system for an internal combustion engine.
It is another object of this invention to provide a lubricating system for an internal combustion engine that insures lubrication of the camshaft lobes and related mechanism even during starting.